How to store IPFS hash on ink! smart contract?

Question

I'm working on an ink! smart contract that will store the IPFS hash for each AccountId. I see that in EVM it's efficient to convert the hash to bytes32. What about in ink!, is Vec<u8> efficient enough?

#[ink(storage)]
pub struct MyContract {
    cids: Mapping<AccountId, Vec<u8>>,
}

Answer 1

Since the IPFS hash is fixed length (32 bytes), you can use [u8; 32] array instead of Vec<u8> which is more efficient.